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Burke Ó, Zeden MS, O'Gara JP. The pathogenicity and virulence of the opportunistic pathogen Staphylococcus epidermidis. Virulence 2024; 15:2359483. [PMID: 38868991 DOI: 10.1080/21505594.2024.2359483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 05/19/2024] [Indexed: 06/14/2024] Open
Abstract
The pervasive presence of Staphylococcus epidermidis and other coagulase-negative staphylococci on the skin and mucous membranes has long underpinned a casual disregard for the infection risk that these organisms pose to vulnerable patients in healthcare settings. Prior to the recognition of biofilm as an important virulence determinant in S. epidermidis, isolation of this microorganism in diagnostic specimens was often overlooked as clinically insignificant with potential delays in diagnosis and onset of appropriate treatment, contributing to the establishment of chronic infection and increased morbidity or mortality. While impressive progress has been made in our understanding of biofilm mechanisms in this important opportunistic pathogen, research into other virulence determinants has lagged S. aureus. In this review, the broader virulence potential of S. epidermidis including biofilm, toxins, proteases, immune evasion strategies and antibiotic resistance mechanisms is surveyed, together with current and future approaches for improved therapeutic interventions.
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Affiliation(s)
- Órla Burke
- Microbiology, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
| | | | - James P O'Gara
- Microbiology, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
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2
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Bonesso MF, Fortaleza CMCB, Cavalcante RDS, Sobrinho MT, Ronchi CF, Abraão LM, Joo HS, Otto M, Ribeiro de Souza da Cunha MDL. A Study on the Epidemiological-Molecular Role of Staphylococcus aureus Strains in the Development of Ventilator-Associated Pneumonia in a Tertiary Hospital in Brazil. Antibiotics (Basel) 2023; 12:1336. [PMID: 37627756 PMCID: PMC10451267 DOI: 10.3390/antibiotics12081336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 08/04/2023] [Accepted: 08/14/2023] [Indexed: 08/27/2023] Open
Abstract
This study aimed to explore the molecular epidemiology of Staphylococcus aureus isolated from patients on mechanical ventilation and the participation of virulence factors in the development of ventilator-associated pneumonia (VAP). A prospective cohort study was conducted on patients under mechanical ventilation, with periodic visits for the collection of tracheal aspirates and clinical data. The S. aureus isolates were analyzed regarding resistance profile, virulence, expression of protein A and alpha-toxin using Western blot, clonal profile using PFGE, sequence type using MLST, and characterization and quantification of phenol-soluble modulins. Among the 270 patients in the study, 51 S. aureus strains were isolated from 47 patients. The incidence density of S. aureus and MRSA VAP was 2.35/1000 and 1.96/1000 ventilator days, respectively; of these, 45% (n = 5) were resistant to oxacillin, with 100% (n = 5) harboring SCCmec types II and IV. The most frequent among the tested virulence factors were icaA, hla, and hld. The clonal profile showed a predominance of sequence types originating from the community. Risk factors for VAP were the presence of solid tumors and the sea gene. In conclusion, patient-related risk factors, together with microbiological factors, are involved in the development of S. aureus VAP, which is caused by the patient's own strains.
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Affiliation(s)
- Mariana Fávero Bonesso
- Department of Infectology, Dermatology, Diagnostic Imaging and Radiotherapy, Medical School (FMB) of Sao Paulo State University (UNESP), Botucatu 18618-970, Brazil; (C.M.C.B.F.); (R.d.S.C.)
- Department of Chemical and Biological Sciences, Biosciences Institute, UNESP—Universidade Estadual Paulista, Botucatu 18618-691, Brazil
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, Bethesda, MD 20814, USA; (H.-S.J.); (M.O.)
| | - Carlos Magno Castelo Branco Fortaleza
- Department of Infectology, Dermatology, Diagnostic Imaging and Radiotherapy, Medical School (FMB) of Sao Paulo State University (UNESP), Botucatu 18618-970, Brazil; (C.M.C.B.F.); (R.d.S.C.)
| | - Ricardo de Souza Cavalcante
- Department of Infectology, Dermatology, Diagnostic Imaging and Radiotherapy, Medical School (FMB) of Sao Paulo State University (UNESP), Botucatu 18618-970, Brazil; (C.M.C.B.F.); (R.d.S.C.)
| | - Moises Teixeira Sobrinho
- Hospital das Clínicas, Botucatu Medical School, University of Sao Paulo State, Botucatu 18618-687, Brazil; (M.T.S.); (C.F.R.)
| | - Carlos Fernando Ronchi
- Hospital das Clínicas, Botucatu Medical School, University of Sao Paulo State, Botucatu 18618-687, Brazil; (M.T.S.); (C.F.R.)
| | - Lígia Maria Abraão
- Nursing Research and Care Practices, Hospital Samaritano Higienópolis, São Paulo 01232-010, Brazil;
| | - Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, Bethesda, MD 20814, USA; (H.-S.J.); (M.O.)
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, Bethesda, MD 20814, USA; (H.-S.J.); (M.O.)
| | - Maria de Lourdes Ribeiro de Souza da Cunha
- Department of Infectology, Dermatology, Diagnostic Imaging and Radiotherapy, Medical School (FMB) of Sao Paulo State University (UNESP), Botucatu 18618-970, Brazil; (C.M.C.B.F.); (R.d.S.C.)
- Department of Chemical and Biological Sciences, Biosciences Institute, UNESP—Universidade Estadual Paulista, Botucatu 18618-691, Brazil
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3
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Li Y, Pan T, Cao R, Li W, He Z, Sun B. Nitrate Reductase NarGHJI Modulates Virulence via Regulation of agr Expression in Methicillin-Resistant Staphylococcus aureus Strain USA300 LAC. Microbiol Spectr 2023; 11:e0359622. [PMID: 37199609 PMCID: PMC10269880 DOI: 10.1128/spectrum.03596-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 04/28/2023] [Indexed: 05/19/2023] Open
Abstract
Staphylococcus aureus is a pathogenic bacterium with a widespread distribution that can cause diverse severe diseases. The membrane-bound nitrate reductase NarGHJI serves respiratory function. However, little is known about its contribution to virulence. In this study, we demonstrated that narGHJI disruption results in the downregulation of virulence genes (e.g., RNAIII, agrBDCA, hla, psmα, and psmβ) and reduces the hemolytic activity of the methicillin-resistant S. aureus (MRSA) strain USA300 LAC. Moreover, we provided evidence that NarGHJI participates in regulating host inflammatory response. A mouse model of subcutaneous abscess and Galleria mellonella survival assay demonstrated that the ΔnarG mutant was significantly less virulent than the wild type. Interestingly, NarGHJI contributes to virulence in an agr-dependent manner, and the role of NarGHJI differs between different S. aureus strains. Our study highlights the novel role of NarGHJI in regulating virulence, thereby providing a new theoretical reference for the prevention and control of S. aureus infection. IMPORTANCE Staphylococcus aureus is a notorious pathogen that poses a great threat to human health. The emergence of drug-resistant strains has significantly increased the difficulty of preventing and treating S. aureus infection and enhanced the pathogenic ability of the bacterium. This indicates the importance of identifying novel pathogenic factors and revealing the regulatory mechanisms through which they regulate virulence. The nitrate reductase NarGHJI is mainly involved in bacterial respiration and denitrification, which can enhance bacterial survival. We demonstrated that narGHJI disruption results in the downregulation of the agr system and agr-dependent virulence genes, suggesting that NarGHJI participates in the regulation of S. aureus virulence in an agr-dependent manner. Moreover, the regulatory approach is strain specific. This study provides a new theoretical reference for the prevention and control of S. aureus infection and reveals new targets for the development of therapeutic drugs.
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Affiliation(s)
- Yujie Li
- Department of Oncology, The First Affiliated Hospital, University of Science and Technology of China, Hefei, People’s Republic of China
- Department of Life Science and Medicine, University of Science and Technology of China, Hefei, People’s Republic of China
| | - Ting Pan
- Department of Oncology, The First Affiliated Hospital, University of Science and Technology of China, Hefei, People’s Republic of China
- Department of Life Science and Medicine, University of Science and Technology of China, Hefei, People’s Republic of China
| | - Ruobing Cao
- Department of Oncology, The First Affiliated Hospital, University of Science and Technology of China, Hefei, People’s Republic of China
- Department of Life Science and Medicine, University of Science and Technology of China, Hefei, People’s Republic of China
| | - Wei Li
- Department of Oncology, The First Affiliated Hospital, University of Science and Technology of China, Hefei, People’s Republic of China
- Department of Life Science and Medicine, University of Science and Technology of China, Hefei, People’s Republic of China
| | - Zhien He
- Department of Oncology, The First Affiliated Hospital, University of Science and Technology of China, Hefei, People’s Republic of China
- Department of Life Science and Medicine, University of Science and Technology of China, Hefei, People’s Republic of China
| | - Baolin Sun
- Department of Oncology, The First Affiliated Hospital, University of Science and Technology of China, Hefei, People’s Republic of China
- Department of Life Science and Medicine, University of Science and Technology of China, Hefei, People’s Republic of China
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Choi JW, Lee Y, Kim J, Kwon H, Deyrup ST, Lee JW, Lee D, Kang HS, Joo H, Shim SH. Discovery of Bioactive Metabolites by Acidic Stress to a Geldanamycin Producer, Streptomyces samsunensis. JOURNAL OF NATURAL PRODUCTS 2023; 86:947-957. [PMID: 37042709 DOI: 10.1021/acs.jnatprod.2c01151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
In an effort to activate silent biosynthetic gene clusters, Streptomyces samsunensis DSM42010, a producer of geldanamycin, was cultured at four different pHs (4.5, 5.4, 6.6, and 7.4). An acidic culture condition (pH 5.4) was selected for a chemical investigation since S. samsunensis showed a different metabolic profile compared to when it was cultured under other conditions. Seven new (1-7) and four known (8-11) compounds were isolated from these cultures. The structures of the isolated compounds were determined by spectroscopic techniques and chemical derivatization. Relative and absolute configurations of the new compounds (1-5) were established using JBCA, PGME method, advanced Marfey's method, modified Mosher's method, and comparison of observed and calculated ECD data. Interestingly, compounds 1-3 were truncated versions of geldanamycin, and compound 4 was also deduced to originate from geldanamycin. Compound 5 was composed of 3-methyltyrosine and 6-hydroxy-2,4-hexadienoic acid connected through an amide bond. Compounds 6 and 7 were dihydrogenated forms of geldanamycin with a hydroxy substitution. It is possible that culturing this strain under acidic conditions interfered to some degree with the geldanamycin polyketide synthase, leading to production of truncated versions as well as analogues of geldanamycin. Compounds 1, 8, and 9 showed significant antivirulence activity, inhibiting production of α-toxin by methicillin-resistant Staphylococcus aureus without growth attenuation and global regulatory inhibition; compounds 1, 8, and 9 may become promising α-toxin-specific antivirulence leads with less risk of resistance development.
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Affiliation(s)
- Jin Won Choi
- Natural Products Research Institute, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Yeonhee Lee
- College of Science and Technology, Duksung Women's University, Seoul 01369, Republic of Korea
| | - Jaekyeong Kim
- Natural Products Research Institute, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Haeun Kwon
- Department of Plant Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 05029, Republic of Korea
| | - Stephen T Deyrup
- Department of Chemistry and Biochemistry, Siena College, Loudonville, New York 12211, United States
| | - Jin Woo Lee
- College of Pharmacy, Duksung Women's University, Seoul 01369, Republic of Korea
| | - Dongho Lee
- Department of Plant Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 05029, Republic of Korea
| | - Hahk-Soo Kang
- Department of Biomedical Science and Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Hwangsoo Joo
- College of Science and Technology, Duksung Women's University, Seoul 01369, Republic of Korea
| | - Sang Hee Shim
- Natural Products Research Institute, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
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5
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Ku H, Lee Y, Lee S, Lee JW, Kang HS, Joo HS, Shim SH. New meroterpenoids from a soil-derived fungus Penicillium sp. SSW03M2 GY and their anti-virulence activity. J Antibiot (Tokyo) 2023; 76:57-64. [PMID: 36526742 DOI: 10.1038/s41429-022-00587-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 11/22/2022] [Accepted: 12/01/2022] [Indexed: 12/23/2022]
Abstract
Two new berkeley meroterpenoids (1 and 2), along with seven known compounds (3‒9) were isolated from a fungus, Penicillium sp. SSW03M2 GY derived from a sediment at Seosan bay, South Korea. Chemical structures of the isolated compounds were elucidated on the basis of 1D, 2D NMR, HRESIMS, and optical rotation. All the isolated compounds, 1 showed anti-virulence activity by significantly inhibiting α-toxin (Hla) secreted by methicillin-resistant Staphylococcus aureus without its growth inhibition.
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Affiliation(s)
- Hyeri Ku
- Natural Products Research Institute, College of Pharmacy, Seoul National University, Seoul, Republic of Korea
| | - Yeonhee Lee
- College of Science and Technology, Duksung Women's University, Seoul, Republic of Korea
| | - Seungjin Lee
- Natural Products Research Institute, College of Pharmacy, Seoul National University, Seoul, Republic of Korea
| | - Jin Woo Lee
- College of Pharmacy, Duksung Women's University, Seoul, Republic of Korea
| | - Hahk-Soo Kang
- Department of Biomedical Science and Engineering, Konkuk University, Seoul, Republic of Korea
| | - Hwang-Soo Joo
- College of Science and Technology, Duksung Women's University, Seoul, Republic of Korea
| | - Sang Hee Shim
- Natural Products Research Institute, College of Pharmacy, Seoul National University, Seoul, Republic of Korea.
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6
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Altwiley D, Brignoli T, Duggan S, Massey RC. Triclosan-resistant small-colony variants of Staphylococcus aureus produce less capsule, less phenol-soluble modulins, and are attenuated in a Galleria mellonella model of infection. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001277. [PMID: 36748621 PMCID: PMC9993119 DOI: 10.1099/mic.0.001277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
In recent work we identified genes that confer the slow-growing and antibiotic-resistant small-colony variant (SCV) form of Staphylococcus aureus, as associated with the amount of capsule the bacteria produce. In this study we isolated a triclosan-resistant SCV (tr-SCV) and demonstrated that it produces significantly less capsule, an effect that appears to be mediated at the transcriptional stage. As with other SCVs, we found that the tr-SCV produces less toxins, and when compared to both a capsule and an Agr mutant we found the tr-SCV to be significantly attenuated in an insect model of infection.
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Affiliation(s)
- Dina Altwiley
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK.,Department of Biological Sciences, University of Jeddah, Jeddah, Saudi Arabia
| | - Tarcisio Brignoli
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK.,Dipartimento di Bioscienze, Università degli studi di Milano, Milan, Italy
| | - Seána Duggan
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK.,MRC Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Ruth C Massey
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK.,Schools of Microbiology and Medicine, and the APC Microbiome Ireland, UCC, Cork, Ireland
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7
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Satishkumar N, Lai LY, Mukkayyan N, Vogel BE, Chatterjee SS. A Nonclassical Mechanism of β-Lactam Resistance in Methicillin-Resistant Staphylococcus aureus and Its Effect on Virulence. Microbiol Spectr 2022; 10:e0228422. [PMID: 36314912 PMCID: PMC9769611 DOI: 10.1128/spectrum.02284-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Accepted: 10/07/2022] [Indexed: 11/07/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a group of pathogenic bacteria that are infamously resistant to β-lactam antibiotics, a property attributed to the mecA gene. Recent studies have reported that mutations associated with the promoter region of pbp4 demonstrated high levels of β-lactam resistance, suggesting the role of PBP4 as an important non-mecA mediator of β-lactam resistance. The pbp4-promoter-associated mutations have been detected in strains with or without mecA. Our previous studies that were carried out in strains devoid of mecA described that pbp4-promoter-associated mutations lead to PBP4 overexpression and β-lactam resistance. In this study, by introducing various pbp4-promoter-associated mutations in the genome of a MRSA strain, we demonstrate that PBP4 overexpression can supplement mecA-associated resistance in S. aureus and can lead to increased β-lactam resistance. The promoter and regulatory region of pbp4 is shared with a divergently transcribed gene, abcA, which encodes a multidrug exporter. We demonstrate that the promoter mutations caused an upregulation of pbp4 and downregulation of abcA, confirming that the resistant phenotype is associated with PBP4 overexpression. PBP4 has also been associated with staphylococcal pathogenesis, however, its exact role remains unclear. Using a Caenorhabditis elegans model, we demonstrate that strains having increased PBP4 expression are less virulent than wild-type strains, suggesting that β-lactam resistance mediated via PBP4 likely comes at the cost of virulence. IMPORTANCE Our study demonstrates the ability of PBP4 to be an important mediator of β-lactam resistance in not only methicillin-susceptible Staphylococcus aureus (MSSA) background strains as previously demonstrated but also in MRSA strains. When present together, PBP2a and PBP4 overexpression can produce increased levels of β-lactam resistance, causing complications in treatment. Thus, this study suggests the importance of monitoring PBP4-associated resistance in clinical settings, as well as understanding the mechanistic basis of associated resistance, so that treatments targeting PBP4 may be developed. This study also demonstrates that S. aureus strains with increased PBP4 expression are less pathogenic, providing important hints about the role of PBP4 in S. aureus resistance and pathogenesis.
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Affiliation(s)
- Nidhi Satishkumar
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, Maryland, USA
- Institute of Marine and Environmental Technology (IMET), Baltimore, Maryland, USA
| | - Li-Yin Lai
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, Maryland, USA
- Institute of Marine and Environmental Technology (IMET), Baltimore, Maryland, USA
| | - Nagaraja Mukkayyan
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, Maryland, USA
- Institute of Marine and Environmental Technology (IMET), Baltimore, Maryland, USA
| | - Bruce E. Vogel
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Som S. Chatterjee
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, Maryland, USA
- Institute of Marine and Environmental Technology (IMET), Baltimore, Maryland, USA
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Study of SarA by DNA Affinity Capture Assay (DACA) Employing Three Promoters of Key Virulence and Resistance Genes in Methicillin-Resistant Staphylococcus aureus. Antibiotics (Basel) 2022; 11:antibiotics11121714. [PMID: 36551372 PMCID: PMC9774152 DOI: 10.3390/antibiotics11121714] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/21/2022] [Accepted: 11/25/2022] [Indexed: 11/29/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA), one of the most well-known human pathogens, houses many virulence factors and regulatory proteins that confer resistance to diverse antibiotics. Although they have been investigated intensively, the correlations among virulence factors, regulatory proteins and antibiotic resistance are still elusive. We aimed to identify the most significant global MRSA regulator by concurrently analyzing protein-binding and several promoters under same conditions and at the same time point. DNA affinity capture assay (DACA) was performed with the promoters of mecA, sarA, and sarR, all of which significantly impact survival of MRSA. Here, we show that SarA protein binds to all three promoters. Consistent with the previous reports, ΔsarA mutant exhibited weakened antibiotic resistance to oxacillin and reduced biofilm formation. Additionally, production and activity of many virulence factors such as phenol-soluble modulins (PSM), α-hemolysin, motility, staphyloxanthin, and other related proteins were decreased. Comparing the sequence of SarA with that of clinical strains of various lineages showed that all sequences were highly conserved, in contrast to that observed for AgrA, another major regulator of virulence and resistance in MRSA. We have demonstrated that SarA regulates antibiotic resistance and the expression of various virulence factors. Our results warrant that SarA could be a leading target for developing therapeutic agents against MRSA infections.
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Reshamwala K, Cheung GYC, Hsieh RC, Liu R, Joo HS, Zheng Y, Bae JS, Nguyen TH, Villaruz AE, Gozalo AS, Elkins WR, Otto M. Identification and characterization of the pathogenic potential of phenol-soluble modulin toxins in the mouse commensal Staphylococcus xylosus. Front Immunol 2022; 13:999201. [PMID: 36189200 PMCID: PMC9520458 DOI: 10.3389/fimmu.2022.999201] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 08/25/2022] [Indexed: 11/16/2022] Open
Abstract
In contrast to the virulent human skin commensal Staphylococcus aureus, which secretes a plethora of toxins, other staphylococci have much reduced virulence. In these species, commonly the only toxins are those of the phenol-soluble modulin (PSM) family. PSMs are species-specific and have only been characterized in a limited number of species. S. xylosus is a usually innocuous commensal on the skin of mice and other mammals. Prompted by reports on the involvement of PSMs in atopic dermatitis (AD) and the isolation of S. xylosus from mice with AD-like symptoms, we here identified and characterized PSMs of S. xylosus with a focus on a potential involvement in AD phenotypes. We found that most clinical S. xylosus strains produce two PSMs, one of the shorter α- and one of the longer β-type, which were responsible for almost the entire lytic and pro-inflammatory capacities of S. xylosus. Importantly, PSMα of S. xylosus caused lysis and degranulation of mast cells at degrees higher than that of S. aureus δ-toxin, the main PSM previously associated with AD. However, S. xylosus did not produce significant AD symptoms in wild-type mice as opposed to S. aureus, indicating that promotion of AD by S. xylosus likely requires a predisposed host. Our study indicates that non-specific cytolytic potency rather than specific interaction underlies PSM-mediated mast cell degranulation and suggest that the previously reported exceptional potency of δ-toxin of S. aureus is due to its high-level production. Furthermore, they suggest that species that produce cytolytic PSMs, such as S. xylosus, all have the capacity to promote AD, but a high combined level of PSM cytolytic potency is required to cause AD in a non-predisposed host.
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Affiliation(s)
- Kunal Reshamwala
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), United States (US) National Institutes of Health (NIH), Bethesda, MD, United States
| | - Gordon Y. C. Cheung
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), United States (US) National Institutes of Health (NIH), Bethesda, MD, United States
- *Correspondence: Michael Otto, ; Gordon Y. C. Cheung,
| | - Roger C. Hsieh
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), United States (US) National Institutes of Health (NIH), Bethesda, MD, United States
| | - Ryan Liu
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), United States (US) National Institutes of Health (NIH), Bethesda, MD, United States
| | - Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), United States (US) National Institutes of Health (NIH), Bethesda, MD, United States
| | - Yue Zheng
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), United States (US) National Institutes of Health (NIH), Bethesda, MD, United States
| | - Justin S. Bae
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), United States (US) National Institutes of Health (NIH), Bethesda, MD, United States
| | - Thuan H. Nguyen
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), United States (US) National Institutes of Health (NIH), Bethesda, MD, United States
| | - Amer E. Villaruz
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), United States (US) National Institutes of Health (NIH), Bethesda, MD, United States
| | - Alfonso S. Gozalo
- Comparative Medicine Branch (CMB), NIAID, NIH, Bethesda, MD, United States
| | - William R. Elkins
- Comparative Medicine Branch (CMB), NIAID, NIH, Bethesda, MD, United States
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), United States (US) National Institutes of Health (NIH), Bethesda, MD, United States
- *Correspondence: Michael Otto, ; Gordon Y. C. Cheung,
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10
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Manna AC, Leo S, Girel S, González-Ruiz V, Rudaz S, Francois P, Cheung AL. Teg58, a small regulatory RNA, is involved in regulating arginine biosynthesis and biofilm formation in Staphylococcus aureus. Sci Rep 2022; 12:14963. [PMID: 36056144 PMCID: PMC9440087 DOI: 10.1038/s41598-022-18815-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 08/19/2022] [Indexed: 12/02/2022] Open
Abstract
Staphylococcus aureus adapts to different environments by sensing and responding to diverse environmental cues. The responses are coordinately regulated by regulatory proteins, and small regulatory RNAs at the transcriptional and translational levels. Here, we characterized teg58, a SarA repressed sRNA, using ChIP-Seq and RNA-Seq analysis of a sarA mutant. Phenotypic and genetic analyses indicated that inactivation of teg58 led to reduced biofilm formation in a process that is independent of SarA, agr, PIA, and PSMs. RNA-Seq analysis of teg58 mutant revealed up-regulation of arginine biosynthesis genes (i.e., argGH) as well as the ability of the mutant to grow in a chemical defined medium (CDM) lacking L-arginine. Exogenous L-arginine or endogenous induction of argGH led to decreased biofilm formation in parental strains. Further analysis in vitro and in vivo demonstrated that the specific interaction between teg58 and the argGH occurred at the post-transcriptional level to repress arginine synthesis. Biochemical and genetic analyses of various arginine catabolic pathway genes demonstrated that the catabolic pathway did not play a significant role in reduced biofilm formation in the teg58 mutant. Overall, results suggest that teg58 is a regulatory sRNA that plays an important role in modulating arginine biosynthesis and biofilm formation in S. aureus.
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Affiliation(s)
- Adhar C Manna
- Department of Microbiology & Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH, 03755, USA.
| | - Stefano Leo
- Genomic Research Laboratory, Service of Infectious Diseases, Geneva University Hospitals and University Medical Center, Rue Michel-Servet 1, 1211, Geneva 4, Switzerland
| | - Sergey Girel
- Institute of Pharmaceutical Sciences of Western Switzerland (ISPSO), School of Pharmaceutical Sciences, University of Geneva, Geneva, Switzerland
- University Medical Center, Rue Michel-Servet 1, 1211, Geneva 4, Switzerland
| | - Víctor González-Ruiz
- Institute of Pharmaceutical Sciences of Western Switzerland (ISPSO), School of Pharmaceutical Sciences, University of Geneva, Geneva, Switzerland
- University Medical Center, Rue Michel-Servet 1, 1211, Geneva 4, Switzerland
| | - Serge Rudaz
- Institute of Pharmaceutical Sciences of Western Switzerland (ISPSO), School of Pharmaceutical Sciences, University of Geneva, Geneva, Switzerland
- University Medical Center, Rue Michel-Servet 1, 1211, Geneva 4, Switzerland
| | - Patrice Francois
- Genomic Research Laboratory, Service of Infectious Diseases, Geneva University Hospitals and University Medical Center, Rue Michel-Servet 1, 1211, Geneva 4, Switzerland
| | - Ambrose L Cheung
- Department of Microbiology & Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH, 03755, USA
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11
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McKellar SW, Ivanova I, Arede P, Zapf RL, Mercier N, Chu LC, Mediati DG, Pickering AC, Briaud P, Foster RG, Kudla G, Fitzgerald JR, Caldelari I, Carroll RK, Tree JJ, Granneman S. RNase III CLASH in MRSA uncovers sRNA regulatory networks coupling metabolism to toxin expression. Nat Commun 2022; 13:3560. [PMID: 35732654 PMCID: PMC9217828 DOI: 10.1038/s41467-022-31173-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 06/03/2022] [Indexed: 01/13/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterial pathogen responsible for significant human morbidity and mortality. Post-transcriptional regulation by small RNAs (sRNAs) has emerged as an important mechanism for controlling virulence. However, the functionality of the majority of sRNAs during infection is unknown. To address this, we performed UV cross-linking, ligation, and sequencing of hybrids (CLASH) in MRSA to identify sRNA-RNA interactions under conditions that mimic the host environment. Using a double-stranded endoribonuclease III as bait, we uncovered hundreds of novel sRNA-RNA pairs. Strikingly, our results suggest that the production of small membrane-permeabilizing toxins is under extensive sRNA-mediated regulation and that their expression is intimately connected to metabolism. Additionally, we also uncover an sRNA sponging interaction between RsaE and RsaI. Taken together, we present a comprehensive analysis of sRNA-target interactions in MRSA and provide details on how these contribute to the control of virulence in response to changes in metabolism.
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Affiliation(s)
- Stuart W McKellar
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Ivayla Ivanova
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Pedro Arede
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Rachel L Zapf
- Department of Biological Sciences, Ohio University, Athens, OH, 45701, USA
| | - Noémie Mercier
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67000, Strasbourg, France
| | - Liang-Cui Chu
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Daniel G Mediati
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, 2052, NSW, Australia
| | - Amy C Pickering
- The Roslin Institute and Edinburgh Infectious Diseases, University of Edinburgh, Easter Bush Campus, Edinburgh, Scotland, UK
| | - Paul Briaud
- Department of Biological Sciences, Ohio University, Athens, OH, 45701, USA
| | - Robert G Foster
- MRC Human Genetics Unit, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - Grzegorz Kudla
- MRC Human Genetics Unit, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - J Ross Fitzgerald
- The Roslin Institute and Edinburgh Infectious Diseases, University of Edinburgh, Easter Bush Campus, Edinburgh, Scotland, UK
| | - Isabelle Caldelari
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67000, Strasbourg, France
| | - Ronan K Carroll
- Department of Biological Sciences, Ohio University, Athens, OH, 45701, USA
- The Infectious and Tropical Disease Institute, Ohio University, Athens, OH, 45701, USA
| | - Jai J Tree
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, 2052, NSW, Australia
| | - Sander Granneman
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, EH9 3BF, UK.
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12
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Thymol Reduces agr-Mediated Virulence Factor Phenol-Soluble Modulin Production in Staphylococcus aureus. BIOMED RESEARCH INTERNATIONAL 2022; 2022:8221622. [PMID: 35586806 PMCID: PMC9110180 DOI: 10.1155/2022/8221622] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 04/08/2022] [Accepted: 04/23/2022] [Indexed: 12/12/2022]
Abstract
Staphylococcus aureus is a major human bacterial pathogen that carries a large number of virulence factors. Many virulence factors of S. aureus are regulated by the accessory gene regulator (agr) quorum-sensing system. Phenol-soluble modulins (PSMs) are one of the agr-mediated virulence determinants known to play a significant role in S. aureus pathogenesis. In the present study, the efficacy of thymol to inhibit PSM production including δ-toxin in S. aureus was explored. We employed liquid chromatography-mass spectrometry (LC-MS) to quantify the PSMsα1-PSMα4, PSMβ1 and PSMβ2, and δ-toxin production from culture supernatants. We found that thymol at 0.5 MIC (128 μg/mL) significantly reduced the PSMα and δ-toxin production in S. aureus WKZ-1, WKZ-2, LAC USA300, and ATCC29213. Downregulation in transcription by quantitative real-time (qRT) PCR analysis of response regulator agrA and receptor histidine kinase agrC upon 0.5 MIC thymol treatment affirmed the results of LC-MS quantification of PSMs. In silico molecular docking analysis demonstrated the binding affinity of thymol with receptors AgrA and AgrC. Transmission electron microscopy images revealed no ultrastructural alterations (cell wall and membrane) in thymol-treated WKZ-1 and WKZ-2 S. aureus strains. Here, we demonstrated that thymol reduces various PSM production in S. aureus clinical isolates and reference strains with mass spectrometry.
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13
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O'Neill AM, Worthing KA, Kulkarni N, Li F, Nakatsuji T, McGrosso D, Mills RH, Kalla G, Cheng JY, Norris JM, Pogliano K, Pogliano J, Gonzalez DJ, Gallo RL. Antimicrobials from a feline commensal bacterium inhibit skin infection by drug-resistant S. pseudintermedius. eLife 2021; 10:66793. [PMID: 34664551 PMCID: PMC8592530 DOI: 10.7554/elife.66793] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 10/02/2021] [Indexed: 12/13/2022] Open
Abstract
Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is an important emerging zoonotic pathogen that causes severe skin infections. To combat infections from drug-resistant bacteria, the transplantation of commensal antimicrobial bacteria as a therapeutic has shown clinical promise. We screened a collection of diverse staphylococcus species from domestic dogs and cats for antimicrobial activity against MRSP. A unique strain (S. felis C4) was isolated from feline skin that inhibited MRSP and multiple gram-positive pathogens. Whole genome sequencing and mass spectrometry revealed several secreted antimicrobials including a thiopeptide bacteriocin micrococcin P1 and phenol-soluble modulin beta (PSMβ) peptides that exhibited antimicrobial and anti-inflammatory activity. Fluorescence and electron microscopy revealed that S. felis antimicrobials inhibited translation and disrupted bacterial but not eukaryotic cell membranes. Competition experiments in mice showed that S. felis significantly reduced MRSP skin colonization and an antimicrobial extract from S. felis significantly reduced necrotic skin injury from MRSP infection. These findings indicate a feline commensal bacterium that could be utilized in bacteriotherapy against difficult-to-treat animal and human skin infections.
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Affiliation(s)
- Alan M O'Neill
- Department of Dermatology, University of California, San Diego, San Diego, United States
| | - Kate A Worthing
- College of Veterinary Medicine, University of Arizona, Oro Valley, United States
| | - Nikhil Kulkarni
- Department of Dermatology, University of California, San Diego, San Diego, United States
| | - Fengwu Li
- Department of Dermatology, University of California, San Diego, San Diego, United States
| | - Teruaki Nakatsuji
- Department of Dermatology, University of California, San Diego, San Diego, United States
| | - Dominic McGrosso
- Department of Pharmacology, University of California, San Diego, San Diego, United States.,Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, San Diego, United States
| | - Robert H Mills
- Department of Pharmacology, University of California, San Diego, San Diego, United States.,Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, San Diego, United States
| | - Gayathri Kalla
- Division of Biological Sciences, University of California, San Diego, San Diego, United States
| | - Joyce Y Cheng
- Department of Dermatology, University of California, San Diego, San Diego, United States
| | - Jacqueline M Norris
- Sydney School of Veterinary Science, University of Sydney, Sydney, Australia
| | - Kit Pogliano
- Division of Biological Sciences, University of California, San Diego, San Diego, United States
| | - Joe Pogliano
- Division of Biological Sciences, University of California, San Diego, San Diego, United States
| | - David J Gonzalez
- Department of Pharmacology, University of California, San Diego, San Diego, United States.,Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, San Diego, United States
| | - Richard L Gallo
- Department of Dermatology, University of California, San Diego, San Diego, United States
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14
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Song HS, Bhatia SK, Choi TR, Gurav R, Kim HJ, Lee SM, Park SL, Lee HS, Joo HS, Kim W, Seo SO, Yang YH. Increased Antibiotic Resistance of Methicillin-Resistant Staphylococcus aureus USA300 Δ psm Mutants and a Complementation Study of Δ psm Mutants Using Synthetic Phenol-Soluble Modulins. J Microbiol Biotechnol 2021; 31:115-122. [PMID: 33046680 PMCID: PMC9705694 DOI: 10.4014/jmb.2007.07034] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 09/11/2020] [Accepted: 10/05/2020] [Indexed: 12/15/2022]
Abstract
Phenol-soluble modulins (PSMs) are responsible for regulating biofilm formation, persister cell formation, pmtR expression, host cell lysis, and anti-bacterial effects. To determine the effect of psm deletion on methicillin-resistant Staphylococcus aureus, we investigated psm deletion mutants including Δpsmα, Δpsmβ, and Δpsmαβ;. These mutants exhibited increased β-lactam antibiotic resistance to ampicillin and oxacillin that was shown to be caused by increased Nacetylmannosamine kinase (nanK) mRNA expression, which regulates persister cell formation, leading to changes in the pattern of phospholipid fatty acids resulting in increased anteiso-C15:0, and increased membrane hydrophobicity with the deletion of PSMs. When synthetic PSMs were applied to Δpsmα and Δpsmβ mutants, treatment of Δpsmα with PSMα1-4 and Δpsmβ with PSMβ1-2 restored the sensitivity to oxacillin and slightly reduced the biofilm formation. Addition of a single fragment showed that α1, α2, α3, and β2 had an inhibiting effect on biofilms in Δpsmα; however, β1 showed an enhancing effect on biofilms in Δpsmβ. This study demonstrates a possible reason for the increased antibiotic resistance in psm mutants and the effect of PSMs on biofilm formation.
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Affiliation(s)
- Hun-Suk Song
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Shashi Kant Bhatia
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea,Institute for Ubiquitous Information Technology and Applications (CBRU), Konkuk University, Seoul 1466, Republic of Korea
| | - Tae-Rim Choi
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Ranjit Gurav
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Hyun Joong Kim
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Sun Mi Lee
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Sol Lee Park
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Hye Soo Lee
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Hwang-Soo Joo
- Department of Biotechnology, College of Engineering, Duksung Women's University, Seoul 0169, Republic of Korea
| | - Wooseong Kim
- College of Pharmacy and Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Seung-Oh Seo
- Department of Food Science and Nutrition, Catholic University of Korea, Bucheon 14662, Republic of Korea,S.O.Seo Fax: +82-2-2164-4316 E-mail:
| | - Yung-Hun Yang
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea,Institute for Ubiquitous Information Technology and Applications (CBRU), Konkuk University, Seoul 1466, Republic of Korea,Corresponding authors Y.H.Yang Fax: +82-2-3437-8360 E-mail:
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15
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A Small Membrane Stabilizing Protein Critical to the Pathogenicity of Staphylococcus aureus. Infect Immun 2020; 88:IAI.00162-20. [PMID: 32571989 PMCID: PMC7440758 DOI: 10.1128/iai.00162-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 06/08/2020] [Indexed: 12/13/2022] Open
Abstract
Staphylococcus aureus is a major human pathogen, and the emergence of antibiotic-resistant strains is making all types of S. aureus infections more challenging to treat. With a pressing need to develop alternative control strategies to use alongside or in place of conventional antibiotics, one approach is the targeting of established virulence factors. However, attempts at this have had little success to date, suggesting that we need to better understand how this pathogen causes disease if effective targets are to be identified. Staphylococcus aureus is a major human pathogen, and the emergence of antibiotic-resistant strains is making all types of S. aureus infections more challenging to treat. With a pressing need to develop alternative control strategies to use alongside or in place of conventional antibiotics, one approach is the targeting of established virulence factors. However, attempts at this have had little success to date, suggesting that we need to better understand how this pathogen causes disease if effective targets are to be identified. To address this, using a functional genomics approach, we have identified a small membrane-bound protein that we have called MspA. Inactivation of this protein results in the loss of the ability of S. aureus to secrete cytolytic toxins, protect itself from several aspects of the human innate immune system, and control its iron homeostasis. These changes appear to be mediated through a change in the stability of the bacterial membrane as a consequence of iron toxicity. These pleiotropic effects on the ability of the pathogen to interact with its host result in significant impairment in the ability of S. aureus to cause infection in both a subcutaneous and sepsis model of infection. Given the scale of the effect the inactivation of MspA causes, it represents a unique and promising target for the development of a novel therapeutic approach.
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16
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Leite EL, Gautron A, Deplanche M, Nicolas A, Ossemond J, Nguyen MT, do Carmo FLR, Gilot D, Azevedo V, Goetz F, Le Loir Y, Otto M, Berkova N. Involvement of caspase-1 in inflammasomes activation and bacterial clearance in S. aureus-infected osteoblast-like MG-63 cells. Cell Microbiol 2020; 22:e13204. [PMID: 32176433 PMCID: PMC10988652 DOI: 10.1111/cmi.13204] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 02/25/2020] [Accepted: 03/05/2020] [Indexed: 12/27/2022]
Abstract
Staphylococcus aureus, a versatile Gram-positive bacterium, is the main cause of bone and joint infections (BJI), which are prone to recurrence. The inflammasome is an immune signaling platform that assembles after pathogen recognition. It activates proteases, most notably caspase-1 that proteolytically matures and promotes the secretion of mature IL-1β and IL-18. The role of inflammasomes and caspase-1 in the secretion of mature IL-1β and in the defence of S. aureus-infected osteoblasts has not yet been fully investigated. We show here that S. aureus-infected osteoblast-like MG-63 but not caspase-1 knock-out CASP1 -/- MG-63 cells, which were generated using CRISPR-Cas9 technology, activate the inflammasome as monitored by the release of mature IL-1β. The effect was strain-dependent. The use of S. aureus deletion and complemented phenole soluble modulins (PSMs) mutants demonstrated a key role of PSMs in inflammasomes-related IL-1β production. Furthermore, we found that the lack of caspase-1 in CASP1 -/- MG-63 cells impairs their defense functions, as bacterial clearance was drastically decreased in CASP1 -/- MG-63 compared to wild-type cells. Our results demonstrate that osteoblast-like MG-63 cells play an important role in the immune response against S. aureus infection through inflammasomes activation and establish a crucial role of caspase-1 in bacterial clearance.
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Affiliation(s)
- Elma Lima Leite
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1253 STLO, Rennes, France; Agrocampus Ouest, Unité Mixtes de Recherche 1253 STLO, Rennes, France
- Instituto de Ciências Biológicas - Universidade Federal de Minas Gerais, Belo Horizonte- Minas Gerais, Brazil
| | - Arthur Gautron
- Univ Rennes, CNRS, IGDR [(Institut de génétique et développement de Rennes)]-UMR 6290, F-35000, Rennes, France
| | - Martine Deplanche
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1253 STLO, Rennes, France; Agrocampus Ouest, Unité Mixtes de Recherche 1253 STLO, Rennes, France
| | - Aurelie Nicolas
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1253 STLO, Rennes, France; Agrocampus Ouest, Unité Mixtes de Recherche 1253 STLO, Rennes, France
| | - Jordane Ossemond
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1253 STLO, Rennes, France; Agrocampus Ouest, Unité Mixtes de Recherche 1253 STLO, Rennes, France
| | - Minh Thu Nguyen
- Paul-Ehrlich-Institute, Federal Regulatory Agency for Vaccines and Biomedicines, Langen 63225, Germany
| | - Fillipe L. R. do Carmo
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1253 STLO, Rennes, France; Agrocampus Ouest, Unité Mixtes de Recherche 1253 STLO, Rennes, France
- Instituto de Ciências Biológicas - Universidade Federal de Minas Gerais, Belo Horizonte- Minas Gerais, Brazil
| | - David Gilot
- Univ Rennes, CNRS, IGDR [(Institut de génétique et développement de Rennes)]-UMR 6290, F-35000, Rennes, France
| | - Vasco Azevedo
- Instituto de Ciências Biológicas - Universidade Federal de Minas Gerais, Belo Horizonte- Minas Gerais, Brazil
| | - Friedrich Goetz
- Mikrobielle Genetik, Universität Tübingen, D-72076 Tübingen, Germany
| | - Yves Le Loir
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1253 STLO, Rennes, France; Agrocampus Ouest, Unité Mixtes de Recherche 1253 STLO, Rennes, France
| | - Michael Otto
- Laboratory of Human Bacterial Pathogenesis, US National Institutes of Health, Bethesda, Maryland, 20892, USA
| | - Nadia Berkova
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1253 STLO, Rennes, France; Agrocampus Ouest, Unité Mixtes de Recherche 1253 STLO, Rennes, France
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17
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Transcriptional regulation of virulence factors Hla and phenol-soluble modulins α by AraC-type regulator Rbf in Staphylococcus aureus. Int J Med Microbiol 2020; 310:151436. [PMID: 32654771 DOI: 10.1016/j.ijmm.2020.151436] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 05/25/2020] [Accepted: 06/14/2020] [Indexed: 12/15/2022] Open
Abstract
Staphylococcus aureus is a gram-positive pathogenic bacterium and is capable of secreting numerous toxins interfering directly with the host to cause acute infections. Rbf, a transcriptional regulator of AraC/XylS family, has been reported to promote biofilm formation in polysaccharide intercellular adhesion (PIA) mediated manner to cause chronic infections. In this study, we revealed the new virulence-mediated role of Rbf that can negatively regulate the hemolytic activity. Furthermore, Rbf can specifically bind to the hla and psmα promoters to repress their expression, resulting in significantly decreased production of phenol-soluble modulins α (PSMα) and alpha-toxin. Accordingly, the rbf mutant strain exhibited the increased pathogenicity compared to the wild-type (WT) strain in a mouse subcutaneous abscess model, representing a type of acute infection by S. aureus. Collectively, our results provide a novel insight into the virulence regulation and acute infections mediated by Rbf in S. aureus.
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18
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Phenol-Soluble Modulin-Mediated Aggregation of Community-Associated Methicillin-Resistant Staphylococcus Aureus in Human Cerebrospinal Fluid. Cells 2020; 9:cells9030788. [PMID: 32214032 PMCID: PMC7140833 DOI: 10.3390/cells9030788] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 03/18/2020] [Accepted: 03/23/2020] [Indexed: 11/16/2022] Open
Abstract
Phenol-soluble modulins (PSMs) are major determinants of Staphylococcus aureus virulence and their increased production in community-associated methicillin-resistant S. aureus (CA-MRSA) likely contributes to the enhanced virulence of MRSA strains. Here, we analyzed the differences in bacterial cell aggregation according to PSM presence in the specific human cerebrospinal fluid (CSF) environment. CSF samples from the intraventricular or lumbar intrathecal area of each patient and tryptic soy broth media were mixed at a 1:1 ratio, inoculated with WT and PSM-deleted mutants (Δpsm) of the CA-MRSA strain, USA300 LAC, and incubated overnight. Cell aggregation images were acquired after culture and image analysis was performed. The cell aggregation ratio in WT samples differed significantly between the two sampling sites (intraventricular: 0.2% vs. lumbar intrathecal: 6.7%, p < 0.001). The cell aggregation ratio in Δpsm samples also differed significantly between the two sampling sites (intraventricular: 0.0% vs. lumbar intrathecal: 1.2%, p < 0.001). Division of the study cases into two groups according to the aggregated area ratio (WT/Δpsm; group A: ratio of ≥ 2, group B: ratio of < 2) showed that the median aggregation ratio value differed significantly between groups A and B (5.5 and 0, respectively, p < 0.001). The differences in CSF distribution and PSM presence within the specific CSF environment are significant factors affecting bacterial cell aggregation.
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19
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Le KY, Villaruz AE, Zheng Y, He L, Fisher EL, Nguyen TH, Ho TV, Yeh AJ, Joo HS, Cheung GYC, Otto M. Role of Phenol-Soluble Modulins in Staphylococcus epidermidis Biofilm Formation and Infection of Indwelling Medical Devices. J Mol Biol 2019; 431:3015-3027. [PMID: 30954574 PMCID: PMC10999989 DOI: 10.1016/j.jmb.2019.03.030] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 03/10/2019] [Accepted: 03/22/2019] [Indexed: 12/20/2022]
Abstract
Phenol-soluble modulins (PSMs) are amphipathic, alpha-helical peptides that are secreted by staphylococci in high amounts in a quorum-sensing-controlled fashion. Studies performed predominantly in Staphylococcus aureus showed that PSMs structure biofilms, which results in reduced biofilm mass, while it has also been reported that S. aureus PSMs stabilize biofilms due to amyloid formation. We here analyzed the roles of PSMs in in vitro and in vivo biofilms of Staphylococcus epidermidis, the leading cause of indwelling device-associated biofilm infection. We produced isogenic deletion mutants for every S. epidermidis psm locus and a sequential deletion mutant in which production of all PSMs was abolished. In vitro analysis substantiated the role of all PSMs in biofilm structuring. PSM-dependent biofilm expansion was not observed, in accordance with our finding that no S. epidermidis PSM produced amyloids. In a mouse model of indwelling device-associated infection, the total psm deletion mutant had a significant defect in dissemination. Notably, the total psm mutant produced a significantly more substantial biofilm on the implanted catheter than the wild-type strain. Our study, which for the first time directly quantified the impact of PSMs on biofilm expansion on an implanted device, shows that the in vivo biofilm infection phenotype in S. epidermidis is in accordance with the PSM biofilm structuring and detachment model, which has important implications for the potential therapeutic application of quorum-sensing blockers.
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Affiliation(s)
- Katherine Y Le
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, MD 20814, USA; Division of Hospital Internal Medicine, Department of Medicine, Mayo Clinic College of Medicine, 200 1st Street SW, Rochester, MN 55902, USA
| | - Amer E Villaruz
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, MD 20814, USA
| | - Yue Zheng
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, MD 20814, USA
| | - Lei He
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, MD 20814, USA; Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, No. 160 Pujian Road, Shanghai 200127, China
| | - Emilie L Fisher
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, MD 20814, USA
| | - Thuan H Nguyen
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, MD 20814, USA
| | - Trung V Ho
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, MD 20814, USA
| | - Anthony J Yeh
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, MD 20814, USA
| | - Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, MD 20814, USA
| | - Gordon Y C Cheung
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, MD 20814, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, MD 20814, USA.
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20
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Keogh RA, Zapf RL, Trzeciak E, Null GG, Wiemels RE, Carroll RK. Novel Regulation of Alpha-Toxin and the Phenol-Soluble Modulins by Peptidyl-Prolyl cis/trans Isomerase Enzymes in Staphylococcus aureus. Toxins (Basel) 2019; 11:toxins11060343. [PMID: 31208155 PMCID: PMC6628628 DOI: 10.3390/toxins11060343] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/10/2019] [Accepted: 06/12/2019] [Indexed: 02/07/2023] Open
Abstract
Peptidyl-prolyl cis/trans isomerases (PPIases) are enzymes that catalyze the cis-to-trans isomerization around proline bonds, allowing proteins to fold into their correct confirmation. Previously, we identified two PPIase enzymes in Staphylococcus aureus (PpiB and PrsA) that are involved in the regulation of virulence determinants and have shown that PpiB contributes to S. aureus virulence in a murine abscess model of infection. Here, we further examine the role of these PPIases in S. aureus virulence and, in particular, their regulation of hemolytic toxins. Using murine abscess and systemic models of infection, we show that a ppiB mutant in a USA300 background is attenuated for virulence but that a prsA mutant is not. Deletion of the ppiB gene leads to decreased bacterial survival in macrophages and nasal epithelial cells, while there is no significant difference when prsA is deleted. Analysis of culture supernatants reveals that a ppiB mutant strain has reduced levels of the phenol-soluble modulins and that both ppiB and prsA mutants have reduced alpha-toxin activity. Finally, we perform immunoprecipitation to identify cellular targets of PpiB and PrsA. Results suggest a novel role for PpiB in S. aureus protein secretion. Collectively, our results demonstrate that PpiB and PrsA influence S. aureus toxins via distinct mechanisms, and that PpiB but not PrsA contributes to disease.
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Affiliation(s)
- Rebecca A Keogh
- Department of Biological Sciences, Ohio University, Athens, OH 45701, USA.
| | - Rachel L Zapf
- Department of Biological Sciences, Ohio University, Athens, OH 45701, USA.
| | - Emily Trzeciak
- Department of Biological Sciences, Ohio University, Athens, OH 45701, USA.
| | - Gillian G Null
- Department of Biological Sciences, Ohio University, Athens, OH 45701, USA.
| | - Richard E Wiemels
- Department of Biological Sciences, Ohio University, Athens, OH 45701, USA.
| | - Ronan K Carroll
- Department of Biological Sciences, Ohio University, Athens, OH 45701, USA.
- The Infectious and Tropical Disease Institute, Ohio University, Athens, OH 45701, USA.
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21
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The Small RNA Teg41 Regulates Expression of the Alpha Phenol-Soluble Modulins and Is Required for Virulence in Staphylococcus aureus. mBio 2019; 10:mBio.02484-18. [PMID: 30723124 PMCID: PMC6428751 DOI: 10.1128/mbio.02484-18] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The alpha phenol-soluble modulins (αPSMs) are among the most potent toxins produced by Staphylococcus aureus. Their biological role during infection has been studied in detail; however, the way they are produced by the bacterial cell is not well understood. In this work, we identify a small RNA molecule called Teg41 that plays an important role in αPSM production by S. aureus. Teg41 positively influences αPSM production. The importance of Teg41 is highlighted by the fact that a strain containing a deletion in the 3′ end of Teg41 produces significantly less αPSMs and is attenuated for virulence in a mouse abscess model of infection. As the search for new therapeutic strategies to combat S. aureus infection proceeds, Teg41 may represent a novel target. Small RNAs (sRNAs) remain an understudied class of regulatory molecules in bacteria in general and in Gram-positive bacteria in particular. In the major human pathogen Staphylococcus aureus, hundreds of sRNAs have been identified; however, only a few have been characterized in detail. In this study, we investigate the role of the sRNA Teg41 in S. aureus virulence. We demonstrate that Teg41, an sRNA divergently transcribed from the locus that encodes the cytolytic alpha phenol-soluble modulin (αPSM) peptides, plays a critical role in αPSM production. Overproduction of Teg41 leads to an increase in αPSM levels and a corresponding increase in hemolytic activity from S. aureus cells and cell-free culture supernatants. To identify regions of Teg41 important for its function, we performed an in silico RNA-RNA interaction analysis which predicted an interaction between the 3′ end of Teg41 and the αPSM transcript. Deleting a 24-nucleotide region from the S. aureus genome, corresponding to the 3′ end of Teg41, led to a 10-fold reduction in αPSM-dependent hemolytic activity and attenuation of virulence in a murine abscess model of infection. Restoration of hemolytic activity in the Teg41Δ3′ strain was possible by expressing full-length Teg41 in trans. Restoration of hemolytic activity was also possible by expressing the 3′ end of Teg41, suggesting that this region of Teg41 is necessary and sufficient for αPSM-dependent hemolysis. Our results show that Teg41 is positively influencing αPSM production, demonstrating for the first time regulation of the αPSM peptides by an sRNA in S. aureus.
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22
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Piewngam P, Zheng Y, Nguyen TH, Dickey SW, Joo HS, Villaruz AE, Glose KA, Fisher EL, Hunt RL, Li B, Chiou J, Pharkjaksu S, Khongthong S, Cheung GYC, Kiratisin P, Otto M. Pathogen elimination by probiotic Bacillus via signalling interference. Nature 2018; 562:532-537. [PMID: 30305736 PMCID: PMC6202238 DOI: 10.1038/s41586-018-0616-y] [Citation(s) in RCA: 334] [Impact Index Per Article: 55.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Accepted: 08/14/2018] [Indexed: 12/19/2022]
Abstract
Probiotic nutrition is frequently claimed to improve human health. In particular, live probiotic bacteria obtained with food are thought to reduce intestinal colonization by pathogens, and thus to reduce susceptibility to infection. However, the mechanisms that underlie these effects remain poorly understood. Here we report that the consumption of probiotic Bacillus bacteria comprehensively abolished colonization by the dangerous pathogen Staphylococcus aureus in a rural Thai population. We show that a widespread class of Bacillus lipopeptides, the fengycins, eliminates S. aureus by inhibiting S. aureus quorum sensing-a process through which bacteria respond to their population density by altering gene regulation. Our study presents a detailed molecular mechanism that underlines the importance of probiotic nutrition in reducing infectious disease. We also provide evidence that supports the biological significance of probiotic bacterial interference in humans, and show that such interference can be achieved by blocking a pathogen's signalling system. Furthermore, our findings suggest a probiotic-based method for S. aureus decolonization and new ways to fight S. aureus infections.
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Affiliation(s)
- Pipat Piewngam
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Yue Zheng
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Thuan H Nguyen
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Seth W Dickey
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
- Department of Pre-PharmMed, College of Natural Sciences, Duksung Women's University, Seoul, South Korea
| | - Amer E Villaruz
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Kyle A Glose
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Emilie L Fisher
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Rachelle L Hunt
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Barry Li
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Janice Chiou
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Sujiraphong Pharkjaksu
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Sunisa Khongthong
- Faculty of Veterinary Science, Rajamangala University of Technology Srivijaya, Nakhon Si Thammarat, Thailand
| | - Gordon Y C Cheung
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Pattarachai Kiratisin
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
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23
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Da F, Joo HS, Cheung GYC, Villaruz AE, Rohde H, Luo X, Otto M. Phenol-Soluble Modulin Toxins of Staphylococcus haemolyticus. Front Cell Infect Microbiol 2017; 7:206. [PMID: 28596942 PMCID: PMC5442197 DOI: 10.3389/fcimb.2017.00206] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 05/08/2017] [Indexed: 12/12/2022] Open
Abstract
Coagulase-negative staphylococci (CoNS) are important nosocomial pathogens and the leading cause of sepsis. The second most frequently implicated species, after Staphylococcus epidermidis, is Staphylococcus haemolyticus. However, we have a significant lack of knowledge about what causes virulence of S. haemolyticus, as virulence factors of this pathogen have remained virtually unexplored. In contrast to the aggressive pathogen Staphylococcus aureus, toxin production has traditionally not been associated with CoNS. Recent findings have suggested that phenol-soluble modulins (PSMs), amphipathic peptide toxins with broad cytolytic activity, are widespread in staphylococci, but there has been no systematic assessment of PSM production in CoNS other than S. epidermidis. Here, we identified, purified, and characterized PSMs of S. haemolyticus. We found three PSMs of the β-type, which correspond to peptides that before were described to have anti-gonococcal activity. We also detected an α-type PSM that has not previously been described. Furthermore, we confirmed that S. haemolyticus does not produce a δ-toxin, as results from genome sequencing had indicated. All four S. haemolyticus PSMs had strong pro-inflammatory activity, promoting neutrophil chemotaxis. Notably, we identified in particular the novel α-type PSM, S. haemolyticus PSMα, as a potent hemolysin and leukocidin. For the first time, our study describes toxins of this important staphylococcal pathogen with the potential to have a significant impact on virulence during blood infection and sepsis.
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Affiliation(s)
- Fei Da
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of HealthBethesda, MD, United States.,Department of Pharmacology, School of Pharmacy, Fourth Military Medical UniversityXi'an, China
| | - Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of HealthBethesda, MD, United States
| | - Gordon Y C Cheung
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of HealthBethesda, MD, United States
| | - Amer E Villaruz
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of HealthBethesda, MD, United States
| | - Holger Rohde
- Institute of Medical Microbiology, Virology, and Hygiene, University Hospital Hamburg-EppendorfHamburg, Germany
| | - Xiaoxing Luo
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical UniversityXi'an, China
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of HealthBethesda, MD, United States
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24
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Qin L, Da F, Fisher EL, Tan DCS, Nguyen TH, Fu CL, Tan VY, McCausland JW, Sturdevant DE, Joo HS, Queck SY, Cheung GYC, Otto M. Toxin Mediates Sepsis Caused by Methicillin-Resistant Staphylococcus epidermidis. PLoS Pathog 2017; 13:e1006153. [PMID: 28151994 PMCID: PMC5289634 DOI: 10.1371/journal.ppat.1006153] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 12/27/2016] [Indexed: 01/03/2023] Open
Abstract
Bacterial sepsis is a major killer in hospitalized patients. Coagulase-negative staphylococci (CNS) with the leading species Staphylococcus epidermidis are the most frequent causes of nosocomial sepsis, with most infectious isolates being methicillin-resistant. However, which bacterial factors underlie the pathogenesis of CNS sepsis is unknown. While it has been commonly believed that invariant structures on the surface of CNS trigger sepsis by causing an over-reaction of the immune system, we show here that sepsis caused by methicillin-resistant S. epidermidis is to a large extent mediated by the methicillin resistance island-encoded peptide toxin, PSM-mec. PSM-mec contributed to bacterial survival in whole human blood and resistance to neutrophil-mediated killing, and caused significantly increased mortality and cytokine expression in a mouse sepsis model. Furthermore, we show that the PSM-mec peptide itself, rather than the regulatory RNA in which its gene is embedded, is responsible for the observed virulence phenotype. This finding is of particular importance given the contrasting roles of the psm-mec locus that have been reported in S. aureus strains, inasmuch as our findings suggest that the psm-mec locus may exert effects in the background of S. aureus strains that differ from its original role in the CNS environment due to originally “unintended” interferences. Notably, while toxins have never been clearly implied in CNS infections, our tissue culture and mouse infection model data indicate that an important type of infection caused by the predominant CNS species is mediated to a large extent by a toxin. These findings suggest that CNS infections may be amenable to virulence-targeted drug development approaches. Coagulase-negative staphylococci (CNS) are the leading cause of sepsis in hospitalized patients, causing a significant number of deaths. This situation is further worsened by a limitation of therapeutic options due to the fact that most CNS infectious isolates are resistant to methicillin. CNS sepsis has been assumed to be due to on over-reacting immune response triggered by invariant bacterial surface structures. By using tissue culture and animal infection model-based evidence, we here show that in contrast to that notion, the PSM-mec toxin produced by methicillin-resistant strains of the leading CNS species Staphylococcus epidermidis has a strong impact on the severity of sepsis and its outcome. This is the first report to link a toxin to the pathogenesis of the most frequent bacterial cause of sepsis. Notably, these findings pave the way for anti-virulence strategies against this widespread and deadly type of infection.
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Affiliation(s)
- Li Qin
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
- Department of Dermatology, Wuhan No.1 Hospital, Tongji Medical College, Huazhong University of Science and Technology (HUST), Wuhan, China
| | - Fei Da
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, China
| | - Emilie L. Fisher
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
| | - Daniel C. S. Tan
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
| | - Thuan H. Nguyen
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
| | - Chih-Lung Fu
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
| | - Vee Y. Tan
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
| | - Joshua W. McCausland
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
| | - Daniel E. Sturdevant
- Research Technology Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Hamilton, Montana, United States of America
| | - Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
| | - Shu Y. Queck
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
| | - Gordon Y. C. Cheung
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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25
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Abstract
The virulence of many bacterial pathogens, including the important human pathogen Staphylococcus aureus, depends on the secretion of frequently large amounts of toxins. Toxin production involves the need for the bacteria to make physiological adjustments for energy conservation. While toxins are primarily targets of gene regulation, such changes may be accomplished by regulatory functions of the toxins themselves. However, mechanisms by which toxins regulate gene expression have remained poorly understood. We show here that the staphylococcal phenol-soluble modulin (PSM) toxins have gene regulatory functions that, in particular, include inducing expression of their own transport system by direct interference with a GntR-type repressor protein. This capacity was most pronounced in PSMs with low cytolytic capacity, demonstrating functional specification among closely related members of that toxin family during evolution. Our study presents a molecular mechanism of gene regulation by a bacterial toxin that adapts bacterial physiology to enhanced toxin production. Toxins play a major role in many bacterial diseases. When toxins are produced during infection, the bacteria need to balance this energy-consuming task with other physiological processes. However, it has remained poorly understood how toxins can impact gene expression to trigger such adaptations. We found that specific members of a toxin family in the major human pathogen Staphylococcus aureus have evolved for gene regulatory purposes. These specific toxins interact with a DNA-binding regulator protein to enable production of the toxin export machinery and ascertain that the machinery is not expressed when toxins are not made and it is not needed. Our study gives mechanistic insight into how toxins may directly adjust bacterial physiology to times of toxin production during infection.
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26
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Mansour SC, Pletzer D, de la Fuente-Núñez C, Kim P, Cheung GYC, Joo HS, Otto M, Hancock REW. Bacterial Abscess Formation Is Controlled by the Stringent Stress Response and Can Be Targeted Therapeutically. EBioMedicine 2016; 12:219-226. [PMID: 27658736 PMCID: PMC5078632 DOI: 10.1016/j.ebiom.2016.09.015] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 09/12/2016] [Accepted: 09/16/2016] [Indexed: 01/08/2023] Open
Abstract
Cutaneous abscess infections are difficult to treat with current therapies and alternatives to conventional antibiotics are needed. Understanding the regulatory mechanisms that govern abscess pathology should reveal therapeutic interventions for these recalcitrant infections. Here we demonstrated that the stringent stress response employed by bacteria to cope and adapt to environmental stressors was essential for the formation of lesions, but not bacterial growth, in a methicillin resistant Staphylococcus aureus (MRSA) cutaneous abscess mouse model. To pharmacologically confirm the role of the stringent response in abscess formation, a cationic peptide that causes rapid degradation of the stringent response mediator, guanosine tetraphosphate (ppGpp), was employed. The therapeutic application of this peptide strongly inhibited lesion formation in mice infected with Gram-positive MRSA and Gram-negative Pseudomonas aeruginosa. Overall, we provide insights into the mechanisms governing abscess formation and a paradigm for treating multidrug resistant cutaneous abscesses. Universal stringent stress response mediators drive abscess formation. Targeting stress response reduces the severity of cutaneous abscess infections. Pharmacological suppression of S. aureus cutaneous toxin production. Paradigm for treating Gram-positive and Gram-negative bacterial abscess infections.
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Affiliation(s)
- Sarah C Mansour
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Daniel Pletzer
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - César de la Fuente-Núñez
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Paul Kim
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Gordon Y C Cheung
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20814, United States
| | - Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20814, United States
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20814, United States
| | - Robert E W Hancock
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
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27
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Li M, Dai Y, Zhu Y, Fu CL, Tan VY, Wang Y, Wang X, Hong X, Liu Q, Li T, Qin J, Ma X, Fang J, Otto M. Virulence determinants associated with the Asian community-associated methicillin-resistant Staphylococcus aureus lineage ST59. Sci Rep 2016; 6:27899. [PMID: 27296890 PMCID: PMC4906288 DOI: 10.1038/srep27899] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 05/25/2016] [Indexed: 11/09/2022] Open
Abstract
Understanding virulence is vital for the development of novel therapeutics to target infections with community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA), which cause an ongoing epidemic in the United States and are on a global rise. However, what defines virulence particularly of global CA-MRSA lineages is poorly understood. Threatening a vast population, the predominant Asian CA-MRSA lineage ST59 is of major epidemiological importance. However, there have been no molecular analyses using defined virulence gene deletion mutants in that lineage as of yet. Here, we compared virulence in skin, lung, and blood infection models of ST59 CA-MRSA isolates with geographically matched hospital-associated MRSA isolates. We selected a representative ST59 CA-MRSA isolate based on toxin expression and virulence characteristics, and produced isogenic gene deletion mutants of important CA-MRSA virulence determinants (α-toxin, PSM α, Agr) in that isolate for in-vitro and in-vivo analyses. Our results demonstrate strongly enhanced virulence of ST59 CA-MRSA over hospital-associated lineages, supporting the notion that enhanced virulence is characteristic for CA-MRSA. Furthermore, they show strong and significant contribution of Agr, α-toxin, and PSMα to pathogenesis of ST59 CA-MRSA skin, lung, and blood infection, emphasizing the value of drug development efforts targeted toward those virulence determinants.
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Affiliation(s)
- Min Li
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Yingxin Dai
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Yuanjun Zhu
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.,Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, USA
| | - Chih-Lung Fu
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, USA
| | - Vee Y Tan
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, USA
| | - Yanan Wang
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Xing Wang
- Department of Laboratory Medicine, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Xufen Hong
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Qian Liu
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Tianming Li
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Juanxiu Qin
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Xiaowei Ma
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Jingyuan Fang
- Department of Gastroenterology and Hepatology, Renji Hospital, School of Medicine, Shanghai Institute of Digestive Disease, Shanghai Jiaotong University, Shanghai, China
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, USA
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28
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Staphylococcus aureus Phenol-Soluble Modulins Impair Interleukin Expression in Bovine Mammary Epithelial Cells. Infect Immun 2016; 84:1682-1692. [PMID: 27001539 DOI: 10.1128/iai.01330-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 03/13/2016] [Indexed: 12/27/2022] Open
Abstract
The role of the recently described interleukin-32 (IL-32) in Staphylococcus aureus-induced mastitis, an inflammation of the mammary gland, is unclear. We determined expression of IL-32, IL-6, and IL-8 in S. aureus- and Escherichia coli-infected bovine mammary gland epithelial cells. Using live bacteria, we found that in S. aureus-infected cells, induction of IL-6 and IL-8 expression was less pronounced than in E. coli-infected cells. Notably, IL-32 expression was decreased in S. aureus-infected cells, while it was increased in E. coli-infected cells. We identified the staphylococcal phenol-soluble modulin (PSM) peptides as key contributors to these effects, as IL-32, IL-6, and IL-8 expression by epithelial cells exposed to psm mutant strains was significantly increased compared to that in cells exposed to the isogenic S. aureus wild-type strain, indicating that PSMs inhibit the production of these interleukins. The use of genetically complemented strains confirmed this observation. Inasmuch as the decreased expression of IL-32, which is involved in dendritic cell maturation, impairs immune responses, our results support a PSM-dependent mechanism that allows for the development of chronic S. aureus-related mastitis.
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29
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AraC-Type Regulator Rsp Adapts Staphylococcus aureus Gene Expression to Acute Infection. Infect Immun 2015; 84:723-34. [PMID: 26712209 DOI: 10.1128/iai.01088-15] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 12/15/2015] [Indexed: 12/24/2022] Open
Abstract
Staphylococcus aureus is an important human pathogen that can cause two categories of severe infections. Acute infections are characterized by pronounced toxin production, while chronic infections often involve biofilm formation. However, it is poorly understood how S. aureus controls the expression of genes associated with acute versus biofilm-associated virulence. We here identified an AraC-type transcriptional regulator, Rsp, that promotes the production of key toxins while repressing major biofilm-associated genes and biofilm formation. Genome-wide transcriptional analysis and modeling of regulatory networks indicated that upregulation of the accessory gene regulator (Agr) and downregulation of the ica operon coding for the biofilm exopolysaccharide polysaccharide intercellular adhesin (PIA) were central to the regulatory impact of Rsp on virulence. Notably, the Rsp protein directly bound to the agrP2 and icaADBC promoters, resulting in strongly increased levels of the Agr-controlled toxins phenol-soluble modulins (PSMs) and alpha-toxin and reduced production of PIA. Accordingly, Rsp was essential for the development of bacteremia and skin infection, representing major types of acute S. aureus infection. Our findings give important insight into how S. aureus adapts the expression of its broad arsenal of virulence genes to promote different types of disease manifestations and identify the Rsp regulator as a potential target for strategies to control acute S. aureus infection.
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Cheung GYC, Yeh AJ, Kretschmer D, Duong AC, Tuffuor K, Fu CL, Joo HS, Diep BA, Li M, Nakamura Y, Nunez G, Peschel A, Otto M. Functional characteristics of the Staphylococcus aureus δ-toxin allelic variant G10S. Sci Rep 2015; 5:18023. [PMID: 26658455 PMCID: PMC4674873 DOI: 10.1038/srep18023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 11/10/2015] [Indexed: 11/25/2022] Open
Abstract
Staphylococcus aureus δ-toxin is a member of the phenol-soluble modulin (PSM) peptide family. PSMs have multiple functions in staphylococcal pathogenesis; for example, they lyse red and white blood cells and trigger inflammatory responses. Compared to other PSMs, δ-toxin is usually more strongly expressed but has only moderate cytolytic capacities. The amino acid sequences of S. aureus PSMs are well conserved with two exceptions, one of which is the δ-toxin allelic variant G10S. This variant is a characteristic of the subspecies S. argenteus and S. aureus sequence types ST1 and ST59, the latter representing the most frequent cause of community-associated infections in Asia. δ-toxin G10S and strains expressing that variant from plasmids or the genome had significantly reduced cytolytic and pro-inflammatory capacities, including in a strain background with pronounced production of other PSMs. However, in murine infection models, isogenic strains expressing the two δ-toxin variants did not cause measurable differences in disease severity. Our findings indicate that the widespread G10S allelic variation of the δ-toxin locus has a significant impact on key pathogenesis mechanisms, but more potent members of the PSM peptide family may overshadow that impact in vivo.
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Affiliation(s)
- Gordon Y C Cheung
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, MD 20892, United States of America
| | - Anthony J Yeh
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, MD 20892, United States of America
| | - Dorothee Kretschmer
- Cellular and Molecular Microbiology Division, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen 72076, Germany
| | - Anthony C Duong
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, MD 20892, United States of America
| | - Kwame Tuffuor
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, MD 20892, United States of America
| | - Chih-Lung Fu
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, MD 20892, United States of America
| | - Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, MD 20892, United States of America
| | - Binh A Diep
- Division of Infectious Diseases, Department of Medicine, University of California, San Francisco, San Francisco, CA 94110, United States of America
| | - Min Li
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200127, China
| | - Yuumi Nakamura
- Department of Dermatology, Chiba University Graduate School of Medicine, Chiba 2608670, Japan
| | - Gabriel Nunez
- Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, United States of America
| | - Andreas Peschel
- Cellular and Molecular Microbiology Division, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen 72076, Germany
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, MD 20892, United States of America
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Cameron DR, Jiang JH, Hassan KA, Elbourne LDH, Tuck KL, Paulsen IT, Peleg AY. Insights on virulence from the complete genome of Staphylococcus capitis. Front Microbiol 2015; 6:980. [PMID: 26441910 PMCID: PMC4585213 DOI: 10.3389/fmicb.2015.00980] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 09/03/2015] [Indexed: 12/28/2022] Open
Abstract
Staphylococcus capitis is an opportunistic pathogen of the coagulase negative staphylococci (CoNS). Functional genomic studies of S. capitis have thus far been limited by a lack of available complete genome sequences. Here, we determined the closed S. capitis genome and methylome using Single Molecule Real Time (SMRT) sequencing. The strain, AYP1020, harbors a single circular chromosome of 2.44 Mb encoding 2304 predicted proteins, which is the smallest of all complete staphylococcal genomes sequenced to date. AYP1020 harbors two large mobile genetic elements; a plasmid designated pAYP1020 (59.6 Kb) and a prophage, ΦAYP1020 (48.5 Kb). Methylome analysis identified significant adenine methylation across the genome involving two distinct methylation motifs (1972 putative 6-methyladenine (m6A) residues identified). Putative adenine methyltransferases were also identified. Comparative analysis of AYP1020 and the closely related CoNS, S. epidermidis RP62a, revealed a host of virulence factors that likely contribute to S. capitis pathogenicity, most notably genes important for biofilm formation and a suite of phenol soluble modulins (PSMs); the expression/production of these factors were corroborated by functional assays. The complete S. capitis genome will aid future studies on the evolution and pathogenesis of the coagulase negative staphylococci.
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Affiliation(s)
- David R Cameron
- Department of Microbiology, Monash University Melbourne, VIC, Australia
| | - Jhih-Hang Jiang
- Department of Microbiology, Monash University Melbourne, VIC, Australia
| | - Karl A Hassan
- Department of Chemistry and Biomolecular Sciences, Macquarie University Sydney, NSW, Australia
| | - Liam D H Elbourne
- Department of Chemistry and Biomolecular Sciences, Macquarie University Sydney, NSW, Australia
| | - Kellie L Tuck
- School of Chemistry, Monash University Melbourne, VIC, Australia
| | - Ian T Paulsen
- Department of Chemistry and Biomolecular Sciences, Macquarie University Sydney, NSW, Australia
| | - Anton Y Peleg
- Department of Microbiology, Monash University Melbourne, VIC, Australia ; Department of Infectious Diseases, Alfred Hospital Melbourne, VIC, Australia
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Role of Phenol-Soluble Modulins in Formation of Staphylococcus aureus Biofilms in Synovial Fluid. Infect Immun 2015; 83:2966-75. [PMID: 25964472 DOI: 10.1128/iai.00394-15] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 05/02/2015] [Indexed: 12/22/2022] Open
Abstract
Staphylococcus aureus is a leading cause of prosthetic joint infections, which, as we recently showed, proceed with the involvement of biofilm-like clusters that cause recalcitrance to antibiotic treatment. Here we analyzed why these clusters grow extraordinarily large, reaching macroscopically visible extensions (>1 mm). We found that while specific S. aureus surface proteins are a prerequisite for agglomeration in synovial fluid, low activity of the Agr regulatory system and subsequent low production of the phenol-soluble modulin (PSM) surfactant peptides cause agglomerates to grow to exceptional dimensions. Our results indicate that PSMs function by disrupting interactions of biofilm matrix molecules, such as the polysaccharide intercellular adhesin (PIA), with the bacterial cell surface. Together, our findings support a two-step model of staphylococcal prosthetic joint infection: As we previously reported, interaction of S. aureus surface proteins with host matrix proteins such as fibrin initiates agglomeration; our present results show that, thereafter, the bacterial agglomerates grow to extremely large sizes owing to the lack of PSM expression under the specific conditions present in joints. Our findings provide a mechanistic explanation for the reported extreme resistance of joint infection to antibiotic treatment, lend support to the notions that Agr functionality and PSM production play a major role in defining different forms of S. aureus infection, and have important implications for antistaphylococcal therapeutic strategies.
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Cheung GYC, Kretschmer D, Duong AC, Yeh AJ, Ho TV, Chen Y, Joo HS, Kreiswirth BN, Peschel A, Otto M. Production of an attenuated phenol-soluble modulin variant unique to the MRSA clonal complex 30 increases severity of bloodstream infection. PLoS Pathog 2014; 10:e1004298. [PMID: 25144687 PMCID: PMC4140855 DOI: 10.1371/journal.ppat.1004298] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 06/20/2014] [Indexed: 12/19/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of morbidity and death. Phenol-soluble modulins (PSMs) are recently-discovered toxins with a key impact on the development of Staphylococcus aureus infections. Allelic variants of PSMs and their potential impact on pathogen success during infection have not yet been described. Here we show that the clonal complex (CC) 30 lineage, a major cause of hospital-associated sepsis and hematogenous complications, expresses an allelic variant of the PSMα3 peptide. We found that this variant, PSMα3N22Y, is characteristic of CC30 strains and has significantly reduced cytolytic and pro-inflammatory potential. Notably, CC30 strains showed reduced cytolytic and chemotactic potential toward human neutrophils, and increased hematogenous seeding in a bacteremia model, compared to strains in which the genome was altered to express non-CC30 PSMα3. Our findings describe a molecular mechanism contributing to attenuated pro-inflammatory potential in a main MRSA lineage. They suggest that reduced pathogen recognition via PSMs allows the bacteria to evade elimination by innate host defenses during bloodstream infections. Furthermore, they underscore the role of point mutations in key S. aureus toxin genes in that adaptation and the pivotal importance PSMs have in defining key S. aureus immune evasion and virulence mechanisms. Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of morbidity and mortality and a great concern for public health. The CC30 MRSA lineage is especially notorious for causing bloodstream infections with complications such as seeding into organs. In our study, we show that this lineage produces an attenuated form of a key S. aureus toxin with decreased pro-inflammatory features. Our results suggest that attenuation of this toxin allows the bacteria to evade recognition and subsequent elimination by host defenses, thereby increasing pathogen success during blood infection.
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Affiliation(s)
- Gordon Y. C. Cheung
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
| | - Dorothee Kretschmer
- Cellular and Molecular Microbiology Division, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Anthony C. Duong
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
| | - Anthony J. Yeh
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
| | - Trung V. Ho
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
| | - Yan Chen
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
| | - Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
| | - Barry N. Kreiswirth
- Public Health Research Institute Tuberculosis Center, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
| | - Andreas Peschel
- Cellular and Molecular Microbiology Division, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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Chen Y, Yeh AJ, Cheung GYC, Villaruz AE, Tan VY, Joo HS, Chatterjee SS, Yu Y, Otto M. Basis of virulence in a Panton-Valentine leukocidin-negative community-associated methicillin-resistant Staphylococcus aureus strain. J Infect Dis 2014; 211:472-80. [PMID: 25139021 DOI: 10.1093/infdis/jiu462] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Community-associated (CA) infections with methicillin-resistant Staphylococcus aureus (MRSA) are on a global rise. However, analysis of virulence characteristics has been limited almost exclusively to the US endemic strain USA300. CA-MRSA strains that do not produce Panton-Valentine leukocidin (PVL) have not been investigated on a molecular level. Therefore, we analyzed virulence determinants in a PVL-negative CA-MRSA strain, ST72, from Korea. Genome-wide analysis identified 3 loci that are unique to that strain, but did not affect virulence. In contrast, phenol-soluble modulins (PSMs) and the global virulence regulator Agr strongly affected lysis of neutrophils and erythrocytes, while α-toxin and Agr had a major impact on in vivo virulence. Our findings substantiate the general key roles these factors play in CA-MRSA virulence. However, our analyses also showed noticeable differences to strain USA300, inasmuch as α-toxin emerged as a much more important factor than PSMs in experimental skin infection caused by ST72.
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Affiliation(s)
- Yan Chen
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Anthony J Yeh
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Gordon Y C Cheung
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Amer E Villaruz
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Vee Y Tan
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Som S Chatterjee
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Yunsong Yu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
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Cheung GYC, Joo HS, Chatterjee SS, Otto M. Phenol-soluble modulins--critical determinants of staphylococcal virulence. FEMS Microbiol Rev 2014; 38:698-719. [PMID: 24372362 DOI: 10.1111/1574-6976.12057] [Citation(s) in RCA: 237] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Revised: 12/05/2013] [Accepted: 12/19/2013] [Indexed: 10/25/2022] Open
Abstract
Phenol-soluble modulins (PSMs) are a recently discovered family of amphipathic, alpha-helical peptides that have multiple roles in staphylococcal pathogenesis and contribute to a large extent to the pathogenic success of virulent staphylococci, such as Staphylococcus aureus. PSMs may cause lysis of many human cell types including leukocytes and erythrocytes, stimulate inflammatory responses, and contribute to biofilm development. PSMs appear to have an original role in the commensal lifestyle of staphylococci, where they facilitate growth and spreading on epithelial surfaces. Aggressive, cytolytic PSMs seem to have evolved from that original role and are mainly expressed in highly virulent S. aureus. Here, we will review the biochemistry, genetics, and role of PSMs in the commensal and pathogenic lifestyles of staphylococci, discuss how diversification of PSMs defines the aggressiveness of staphylococcal species, and evaluate potential avenues to target PSMs for drug development against staphylococcal infections.
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Affiliation(s)
- Gordon Y C Cheung
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, MD, USA
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